bf_compact creates a more compact
	    bogofilter working directory with a
	    dump/load cycle and renames the previous
	    bogofilter_directory to
	    bogofilter_directory.old.
Note: bf_compact cannot be used to process the current working directory, ".", because that cannot be renamed.
If no wordlist_file arguments are
	given, then bf_compact will use the
	configured set of wordlists, if the given
	bogofilter_directory is the same as
	the configured, or use all *.db files if it is a different
	directory.
The script exits with status code 0 if everything went well, and nonzero if it encountered trouble.